System and method for estimating NOx produced by an internal combustion engine
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G06F-019/00
F02D-041/00
출원번호
UP-0928195
(2007-10-30)
등록번호
US-7831378
(2010-11-25)
발명자
/ 주소
Wills, J. Stephen
출원인 / 주소
Cummins Inc.
대리인 / 주소
Barnes & Thornburg LLP
인용정보
피인용 횟수 :
4인용 특허 :
10
초록▼
A system and method are provided for estimating NOx produced by an internal combustion engine. The flow rate of fuel supplied to the engine and a plurality of engine operating parameters are monitored. NOx produced by the engine is estimated based on a product of the flow rate of fuel and a function
A system and method are provided for estimating NOx produced by an internal combustion engine. The flow rate of fuel supplied to the engine and a plurality of engine operating parameters are monitored. NOx produced by the engine is estimated based on a product of the flow rate of fuel and a function of the plurality of engine operating parameters. The NOx estimate is stored in memory.
대표청구항▼
What is claimed is: 1. A method of estimating NOx produced by an internal combustion engine, the method comprising: monitoring a flow rate of fuel supplied to the engine, monitoring a plurality of engine operating parameters, determining a number of model constants, estimating NOx produced by the e
What is claimed is: 1. A method of estimating NOx produced by an internal combustion engine, the method comprising: monitoring a flow rate of fuel supplied to the engine, monitoring a plurality of engine operating parameters, determining a number of model constants, estimating NOx produced by the engine based on a product of a first function and a second function, the first function being a function of the flow rate of fuel and at least one of the model constants, and the second function being a function of the plurality of engine operating parameters and remaining ones of the model constants, and storing the NOx estimate in memory, wherein monitoring a plurality of engine operating parameters comprises determining a charge composition value corresponding to at least a partial composition of charge entering the engine. 2. The method of claim 1 wherein monitoring a flow rate of fuel, monitoring a plurality of engine operating parameters, determining a number of model constants, estimating NOx produced by the engine and storing the NOx estimate in memory are all carried out once per engine cycle. 3. The method of claim 1 wherein storing the NOx estimate in memory comprises adding the NOx estimate to an accumulated NOx estimate value in memory. 4. The method of claim 1 wherein monitoring a plurality of engine operating parameters comprises determining a charge mass value corresponding to at least a partial composition of charge entering the engine. 5. The method of claim 1 wherein monitoring a plurality of engine operating parameters comprises determining a charge temperature value corresponding to a temperature of charge entering the engine. 6. The method of claim 1 wherein monitoring a plurality of engine operating parameters comprises determining a fuel timing value corresponding to a timing of fuel supplied to the engine relative to a reference timing value. 7. The method of claim 1 wherein monitoring a plurality of engine operating parameters comprises determining a rotational speed of the engine. 8. The method of claim 1 wherein monitoring a plurality of engine operating parameters comprises determining an operating temperature of the engine, and wherein determining an operating temperature of the engine comprises determining at least one of a coolant temperature corresponding to a temperature of coolant circulating through the engine and determining a temperature of oil within the engine. 9. The method of claim 1 wherein a fuel system includes a fuel rail fluidly coupled to a number of fuel injectors, the number of fuel injectors configured to selectively supply fuel to the engine from the fuel rail, and wherein monitoring a plurality of engine operating parameters comprises determining a fuel rail pressure corresponding to a pressure of fuel within the fuel rail. 10. The method of claim 1 wherein each of the plurality of engine operating parameters is represented by an engine operating parameter variable TN, where N is a positive integer greater than 1, and wherein estimating NOx comprises estimating NOx produced by the engine (NOxE) according to the equation NOxE=(K*FF)*[(C1*T1)+(C2*T2)+ . . . +(CN*TN)], where FF is the fuel flow rate, and K and C1, C2, . . . CN comprise the number of model constants. 11. A method of estimating NOx produced by an internal combustion engine, the method comprising: determining a fuel flow rate corresponding to a flow rate of fuel supplied to the engine, determining a fuel timing corresponding to a timing of fuel supplied to the engine relative to a reference timing value, determining an engine speed corresponding to rotational speed of the engine, determining a charge mass corresponding to a mass of charge entering the engine, determining a charge composition corresponding to at least a partial composition of charge entering the engine, determining a charge temperature corresponding to a temperature of charge entering the engine, estimating NOx produced by the engine as a function of the fuel flow rate, fuel timing, engine speed, charge mass, charge composition and charge temperature, and storing the NOx estimate in memory. 12. The method of claim 11 wherein determining a fuel flow rate, determining a fuel timing, determining an engine speed, determining a charge mass, determining a charge composition, determining a charge composition, estimating, estimating NOx produced by the engine and storing the NOx estimate in memory are carried out once per engine cycle. 13. The method of claim 11 wherein storing the NOx estimate in memory comprises adding the NOx estimate to an accumulated NOx estimate value in memory. 14. The method of claim 11 wherein estimating NOx comprises estimating NOx produced by the engine (NOxE) according to the function NOxE=(K*FF)*[(C1*CM)+(C2*CC)+(C3*CT)+(C4*FT)+(C5*ES)+C6], where FF is the fuel flow rate, CM is the charge mass, CC is the charge composition, CT is the charge temperature, FT is the fuel timing, ES is the engine speed, and K and C1-C6 are model constants. 15. The method of claim 14 wherein determining a charge mass comprises: determining a charge flow corresponding to a flow rate of charge entering the engine, and determining the charge mass as a function of the charge flow and the engine speed. 16. The method of claim 15 wherein determining a charge composition comprises determining an EGR fraction corresponding to a fraction of recirculated exhaust gas in the charge supplied to the engine. 17. The method of claim 16 wherein determining an EGR fraction comprises: determining an EGR flow corresponding to a flow rate of recirculated exhaust gas entering the engine, and determining the EGR fraction value as a function of the charge flow and the EGR flow. 18. The method of claim 17 wherein determining a charge composition value further comprises: determining a second order EGR fraction value as a function of the EGR fraction value, and computing the charge composition value as a sum of the EGR fraction value and the second order EGR fraction value such that estimating NOx comprises estimating NOx produced by the engine according to the function NOxE=(K*FF)*[(C1f(CF,ES))+(C2*[EGRF+f(EGRF))+(C3*CT)+(C4*FT)+(C5*ES)+C6], where CF is the charge flow, f(CF, ES) is the charge mass, EGRF is the EGR fraction value and f(EGRF) is the second order EGR fraction value. 19. A system for estimating NOx produced by an internal combustion engine, the system comprising: a fuel system coupled to a source of fuel and to the engine and configured to supply fuel from the source of fuel to the engine, means for determining a charge composition value corresponding to at least a partial composition of the charge entering the engine, and a control circuit including a memory having stored therein instructions that are executable by the control circuit to determine a fuel flow value corresponding to a flow rate of fuel supplied by the fuel system to the engine, to determine a plurality of operating parameters associated with operation of the engine, the plurality of operating parameters including the charge composition value, to estimate NOx produced by the engine as a product of the fuel flow value and a function of the plurality of operating parameters and to store the estimated NOx in the memory. 20. The system of claim 19 wherein the memory includes an accumulator having stored therein an accumulated NOx estimate value, and wherein the instructions further include instructions that are executable by the control circuit to store the estimated NOx in the memory by adding the estimated NOx to the accumulated NOx estimate value stored in the memory. 21. The system of claim 19 further comprising: means for determining a charge mass value corresponding to a mass of charge entering the engine, means for determining a charge temperature corresponding to a temperature of the charge entering the engine, means for determining a fuel timing value corresponding to a timing fuel supplied to the engine relative to a reference time value, and means for determining an engine speed value corresponding to a rotational speed of the engine, wherein the plurality of operating parameters associated with operation of the engine include the charge mass value, the charge temperature value, the fuel timing value and the engine speed value. 22. The system of claim 21 further comprising a number of model constants stored in the memory, wherein the instructions further include instructions to estimate the NOx produced by the engine (NOxE) according to the equation NOxE=(K*FF)*[(C1*CM)+(C2*CC)+(C3*CT)+(C4*FT)+(C6*ES)+C6], where FF is the fuel flow rate, CM is the charge mass, CC is the charge composition, CT is the charge temperature, FT is the fuel timing, ES is the engine speed, and K and C1-C6 comprise the number of model constants. 23. The system of claim 22 wherein the means for determining a charge composition value comprises means for determining an EGR fraction value corresponding to a fraction of recirculated exhaust gas in the charge entering the engine. 24. The system of claim 23 wherein the means for determining a charge composition value further comprises means for determining a second order EGR fraction value as a function of the EGR fraction value and for determining the charge composition value as a sum of the EGR fraction value and the second order EGR fraction value.
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이 특허에 인용된 특허 (10)
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